Start preparing this jam by cleaning the apricots. Wash them with water and remove the stones or any rotten parts. You should have 2 kg of chopped fruit. Then put the apricots in a big cooking pot, and cover them with sugar to release the juice. Let them rest for 4-6 hours in a cool place, or you can leave them overnight.
When the apricots have released the juice, add freshly squeezed lemon juice, whizz them with an immersion blender and start cooking.
Cook the jam over lower to medium heat for about 2 - 2,5 hours. During cooking, if foam appears, remove it with the spoon. Stir constantly so it doesn't burn.
When you want to check if the jam is thick enough, grab a teaspoon of hot jam, put it on a small plate, and inside the fridge for 10 minutes. If the density of the jam is to your liking, remove it from the heat. If you want it to be thicker, cook it a bit longer.
When the jam is done, pour it into the jars previously washed in hot water and sterilized at 120°C (248 F) for half an hour in the oven.
Immediately close them tightly with clean, sterilized metal lids and let them cool for 24 hours wrapped in a kitchen towel.
Store the jam in a dark and cool place and keep it for up to a year.